JP2002256699A - Concrete form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete form which employs a recyclable paperboard as a sheathing board, and is repeatedly usable. SOLUTION: The concrete form is formed of the sheathing board 1 consisting of the paperboard 1' obtained by sticking, to each other, a number of water- resistant paperboards which contain 75 wt.% or more recycled wastepaper, polyethylene films 3 laminated on both sides of the paperboard 1', and polyester films 2 laminated on the same via the polyethylene films 3. The concrete form thus formed is easily releasable from concrete and repeatedly usable. After using the concrete form, the paperboard is recyclable as a wastepaper material, and therefore usage of woody plates such as plywood can be reduced, to thereby contribute to resource preservation. Further, formation of vent holes 4 in the sheathing board leads to further increase in release properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete formwork used for placing concrete in construction and civil engineering, and more particularly to a concrete formwork that can be used repeatedly and can be recycled.

[0002]

2. Description of the Related Art Conventionally, wood boards such as plywood, particle board, and hard board have been often used as dams for concrete casting formwork. Although some metal plates and plastic plates are used, wood plates, particularly plywood, are still most frequently used because of their light weight and cost. In the case of a weir board using a wood board such as this plywood,
Acrylic resin, epoxy, etc. on the surface of plywood, etc. A resin or a synthetic resin paint such as a urethane resin is applied, and a release agent is further applied thereon. For example, JP-A-48-20326, JP-A-56-135671, JP-A-57-156571 As disclosed in JP-A-98354 and the like, it has been proposed to coat the surface of a wood board such as plywood with various plastic films such as polyolefin, polyamide, polyester, polyvinyl chloride, and polyurethane.

However, in the conventional concrete formwork using a wood board such as the plywood as a weir board as described above, it cannot be reused for other purposes after being disabled as a formwork. There is no choice but to incinerate. Concrete formwork is used in large quantities in construction and civil engineering work, and incineration of wood resources such as plywood in large quantities is not preferable from the viewpoint of resource protection and environmental protection.

[0004]

SUMMARY OF THE INVENTION In view of the above problems in the conventional concrete form, the present invention can be used repeatedly and can be recycled after use.
An object of the present invention is to provide a concrete formwork that can contribute to the protection of wood resources and the environment without using a wood board such as plywood.

[0005]

In view of the above points, the present inventors have completed a concrete formwork capable of achieving the above object by using a dam board made of paperboard instead of the conventional plywood. I came to.

That is, the concrete formwork according to the present invention comprises:
It is characterized in that a polyester film is adhered to at least a concrete casting surface of a board made of paperboard.

[0007] The concrete formwork according to the present invention as described above has a damping board made of a paperboard surface on which a polyester film is adhered, so that the concrete finished surface is smooth and the concrete surface is like a plywood. Since there is no influence of formalin or the like that inhibits the hardening property and the releasability from the hardened concrete is extremely good, it can be repeatedly used. In addition, since the surface is covered with a polyester film, it is possible to prevent breakage of the paperboard when crushed stones collide with the surface of the weir plate when casting concrete, and furthermore, the polyester film adhered to the surface This also increases the rigidity of the weir plate. In addition, since paperboard is used as the weir board, even if the polyester film on the surface is damaged and becomes unusable as a weir board as a result of repeated use, it can be recycled as waste paper raw material. It can also be used as a dam for concrete formwork, and can contribute to resource protection and environmental protection.

The polyester film may be adhered to at least one side of the paperboard which is to be a concrete casting surface of the weir plate. In the case of a weir plate in which the polyester film is adhered to both sides of the paperboard, the weir plate is used. The water resistance is improved, and the front and back surfaces can be used as a concrete casting surface. Even when one surface becomes unusable, it can be used upside down to increase the number of times of use.

By using a board in which water-resistant paperboard is laminated as the paperboard, it can be used repeatedly without becoming unusable due to wetness and the like. Furthermore, 75% by weight of recycled waste paper is used as the water-resistant paperboard. By using the above, the degree of contribution to resource protection by recycling will be great.

As a method of attaching polyester to the paperboard surface, it is preferable to attach a polyester film via an adhesive layer made of a thermoplastic resin. A thermoplastic resin film can be used as the adhesive layer made of the thermoplastic resin. Further, the thermoplastic resin is preferably a polyolefin-based resin, and among them, polyethylene is particularly preferable in terms of adhesiveness, workability, and cost.

As a method of attaching a polyester film to the surface of paperboard using the above-mentioned thermoplastic resin film, a method of laminating a thermoplastic resin film melted by extrusion lamination on one side of paperboard and a method of laminating the thermoplastic resin By laminating and pressing the polyester film from above the film, the polyester film is adhered to the surface of the paperboard, and the paperboard is laminated with one or more paperboards with the polyester film adhered surface outside. preferable.

Further, if ventilation holes communicating with the paperboard are provided in the polyester film on the surface of the weir plate, the releasability from concrete is improved. In the case where the polyester film is laminated on both sides of the paperboard, it is preferable to provide the ventilation holes in the polyester films on both sides. Further, it is more preferable that the ventilation holes are provided so as to penetrate both sides of the dam plate.

[0013] It is not always clear why the vent hole is provided in the polyester film laminated on the surface of the weir plate as described above to improve the releasability from the hardened concrete, but the following is presumed. . In other words, the polyester film is excellent in mold release properties from concrete, but when the polyester film is repeatedly used as a dam for a concrete form by attaching the polyester film to the surface of paperboard,
The releasability from the hardened concrete deteriorates, and eventually the polyester film peels off from the paperboard, making it unusable as a dam board. This is because although the material of the polyester film itself has excellent releasability from concrete, when the concrete hardens and shrinks, it shrinks when there is a smooth surface layer with the polyester film stuck on the weir plate surface. It is presumed that the smooth dam plate surface layer is adsorbed to the concrete to be adhered to and firmly adheres to the concrete surface. At this time, if the polyester film is provided with a vent, if the concrete hardens, shrinks, the concrete surface communicates with the paperboard inside the weir plate through the vent hole, and further outside the weir plate, It is presumed that the weir plate surface is not adsorbed to the concrete and both adhere to each other, and the mold is easily released from the hardened concrete surface due to the inherent releasability of the polyester film. It is to be noted that this is only an estimation, and it should be added that at this stage, the mechanism of improving the releasability of the weir plate from the hardened concrete by the ventilation hole has not been sufficiently elucidated.

The concrete formwork according to the present invention as described above is preferably used after waterproofing the small end face of the dam board made of paperboard.

Further, in the concrete formwork of the present invention, a wood board such as a plywood, for example,
By joining a synthetic resin plate, a lath plate and the like, the paperboard can be reinforced and used as a weir plate.

The concrete formwork according to the present invention, when used, is reinforced on the back surface of the weir plate made of paperboard as described above or on the back surface of the back plate when the back plate is joined, as a support, at the peripheral edge thereof. And a reinforcing bar is provided inside the reinforcing frame. As described above, the concrete formwork of the present invention in which a reinforcing frame or a reinforcing bar is provided as a support on the back surface of the board made of paperboard is 3.5 ton / ton which is required as a concrete formwork for construction.
m ² , and a pressure resistance of 5.5 ton / m ² or more required as a concrete formwork for civil engineering can be achieved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a concrete formwork of the present invention will be described in more detail with reference to the drawings.

In the concrete formwork of the present invention, for example, as shown in FIG. 1, a polyester film 2 is adhered to both sides of a paperboard 1 ′ via an adhesive layer 3.
The polyester film 2 may be attached to at least one side of the dam plate 1 that is to be a concrete casting surface,
As shown in the figure, a polyester film 2 is provided on both sides of the paperboard 1 '.
The water resistance and strength of the weir plate 1 are improved by sticking. Further, a polyester film 2 is provided on both sides of the paperboard 1 '.
Can be used as a concrete casting surface on both sides, and even if the polyester film 2 on one side is damaged and becomes unusable, it can be used upside down. As a result, the number of times that the weir plate 1 can be used increases.

The thickness of the paperboard 1 'is, for example, 3 mm to 1 mm.
It is preferably about 5 mm, and more preferably about 3 mm to 6 mm. If the thickness of the paperboard 1 'is too thin, the rigidity of the concrete formwork as a weir plate will be insufficient, and if it is too thick, it will be heavy and workability during transport and formwork will be poor. In addition, as described later, the paperboard 1 ′
Even when the thickness is small, it can be used as a dam for concrete formwork by joining and using a back plate such as plywood.

The paperboard 1 'is preferably made of a board in which water-resistant paperboard is bonded in multiple layers, and more preferably, the water-resistant paperboard is made of 75% by weight or more of recycled paper. As described above, by using a paperboard made of a board in which water-resistant paperboard is multilayered as the weir board 1, it can be repeatedly used without becoming unusable due to wetness or the like. The use of recycled paper of 75% by weight or more greatly contributes to resource protection by recycling.

Examples of the polyester film 2 laminated on the surface of the paperboard 1 'include a film made of a polyester resin such as polyethylene terephthalate and polybutylene terephthalate. Although the thickness of the polyester film 2 is not particularly limited, it is required to be about 10 μm to protect the surface of the paperboard 1 ′ and withstand repeated use, preferably 10 to 300 μm.
m, usually about 10 to 50 μm.

As described above, the method of attaching the polyester film 2 to the surface of the paperboard 1 'is not particularly limited, and may be a conventionally known method, for example, a hot melt adhesive, a synthetic rubber adhesive. Adhesion may be performed using an adhesive layer 3 or the like, but it is preferable that the adhesive layer 3 is adhered via an adhesive layer 3 made of a thermoplastic resin. At the same time as laminating the thermoplastic resin film, the polyester film 2 is laminated thereon, and the polyester film 2 is adhered to the surface of the dam plate 1 by pressure contact.

That is, in one preferred embodiment of the dam board of the present invention, a polyester film 2 is adhered to the surface of a paperboard 1 'via an adhesive layer 3 made of a thermoplastic resin. 75% by weight of recycled paper as paperboard 1 '
A board obtained by laminating the above-described waterproof paperboard in a multilayered manner is used, and a polyester film 2 is adhered to both sides of the board via an adhesive layer 3 made of a thermoplastic resin such as polyethylene.

As the recycled paper occupying 75% by weight or more of the water-resistant paperboard, it is preferable to use rigid long fibers such as corrugated paper or wrapping paper. Further, the concrete form using the board made of the water-resistant paperboard as the weir board 1 may be collected after use, and may be repeatedly used as the recycled waste paper raw material. A specific method for producing water-resistant paperboard is a rosin sizing agent, a synthetic sizing agent, a polyacrylamide resin for imparting water resistance to a suspension of a fiber raw material composed of 100% recycled waste paper or pulp. After the paper layer is formed by internally adding a dry paper strength enhancer mainly composed of, for example, and a wet paper strength enhancer mainly composed of an epoxy resin, and a sulfuric acid band for fixing these to the fiber material. , Dehydration and drying. The water-resistant paperboard produced in this manner is manufactured by JI
Water absorbency of 1 minute Cobb method as defined in S-P8140 (moisture weight of water from the surface of 1 m ² per minute to g Display) is 30 g / m ² or less, 24 hours water immersion weight gain rate (10 cm × 10 cm of 24 samples cut to dimensions
After immersion in water for a period of time, the water content on the surface is removed with a filter paper and weighed, and the weight is expressed in terms of the rate of weight increase relative to the original weight).

A board to be used as the dam board 1 of the concrete formwork is produced by laminating the above-mentioned water-resistant paperboard to a desired thickness by multilayer bonding. In this case, the water-resistant paperboard is bonded by pressing with, for example, a polyvinyl alcohol-based or polyvinyl acetate-based water-resistant adhesive. In this way, the water-resistant paperboard is laminated to form a board having a desired thickness, and then cut into a predetermined size to be used as a weir board.

As the polyester film 2 to be adhered to both sides of the paperboard 1 ', a polyester resin material such as polyethylene terephthalate or polybutylene terephthalate formed into a film by a known processing method can be used. The dried resin material is melted and T
A film obtained by extruding with a die or a ring die, cooling to make an amorphous form, subsequently stretching uniaxially or biaxially, and heating it under tension to crystallize it is used.

A specific method for attaching a polyester film 2 to both sides of a paperboard 1 'made of a board to which a large number of the waterproof boards are attached via an adhesive layer 3 made of a thermoplastic resin will be described. First, at the same time as laminating a thermoplastic resin film 3 such as polyethylene melted by extrusion lamination on one surface of one piece of water-resistant paperboard, a polyester film 2 is laminated and pressed from above the thermoplastic resin film 3, The polyester film 2 is stuck on the surface of the water-resistant paperboard. The water-resistant paperboard having the polyester film 2 adhered to one surface in this manner is used as a front material and a back material, and another water-resistant paperboard is placed between the front material and the back material with the polyester film adhering surfaces on the outside. Alternatively, a plurality of sheets are laminated, and the respective waterproof boards are pressed together with a waterproof adhesive to join them, whereby the dam board 1 having the polyester films 2 stuck on both sides can be obtained.

The thickness of the adhesive layer 3 made of the thermoplastic resin is not particularly limited. However, from the viewpoint of the adhesive strength between the polyester film 2 and the paperboard 1 ', it is necessary to have a thickness of at least about 10 μm. About 300 μm, usually 1
The thickness may be about 0 to 50 μm.

As described above, in the concrete formwork according to the present invention, since the polyester film 2 is adhered to the surface of the paperboard 1 'to form the concrete casting surface of the dam board 1, the concrete finished surface is smooth. In addition, there is no influence of formalin or the like that inhibits concrete surface hardening like wood board such as plywood, and the mold releasability from the hardened concrete surface is extremely good, so it can be used repeatedly. . Further, since the surface of the paperboard 1 ′ is covered with the polyester film 2,
It is possible to prevent the paperboard 1 'from being damaged when crushed stones or the like collide with the surface of the dam board 1 at the time of placing concrete, and the rigidity of the dam board 1 is also improved by the polyester film 2 adhered to the surface. . Also, since the weir plate 1 is made of paperboard, even if the polyester film 2 on the surface is damaged and becomes unusable as a weir plate as a result of repeated use, it should be collected and reused as recycled waste paper. And make a great contribution to resource conservation.

Further, as shown in FIG. 2, by providing ventilation holes 4 in the polyester film 2 attached to the surface of the paperboard 1 'as described above, the barrier plate 1 can be separated from the hardened concrete surface. The moldability is improved. In the case where the polyester film 2 is laminated on both sides of the paperboard 1 'as shown in the figure, the ventilation holes 4 may be provided only on one side of the polyester film 2 on both sides which is a concrete casting surface. More preferably, 4 is provided on each of the polyester films 2 on both sides. In this case, the ventilation holes 4 on both surfaces need not always be provided at the same position. Further, as shown in FIG. 3, the ventilation holes 4 can be provided to penetrate the front and back of the weir plate 1, whereby the releasability from the hardened concrete is further improved. Further, as the ventilation hole 4, a non-through hole 4 as shown in FIG. 2 and a through hole 4 as shown in FIG. 3 can be used together.

The polyester film 2 on the surface of the weir plate 1
It is preferable that the size of the ventilation hole 4 provided is such that the solid content of the concrete does not flow out through the ventilation hole 4 to the paperboard 1 ′ and further to the back side of the dam board 1. Preferably, it is small. If the ventilation hole 4 is too large, the solid content of the concrete flows out through the ventilation hole 4 and the smoothness of the concrete finished surface deteriorates, and the concrete flowing into the ventilation hole 4 hardens and becomes an anchor. The releasability of the weir plate 1 from concrete tends to deteriorate, and if the ventilation holes 4 provided in the weir plate 1 are completely closed by the hardened concrete, the releasability by the ventilation holes 4 during repeated use is increased. The improvement effect decreases.

The number of the ventilation holes 4 is not particularly limited, and varies depending on the size of the weir plate 1. The larger the size of the ventilation holes 4, the smaller the number may be. The number of holes 4 may be smaller than that of the non-through holes 4 shown in FIG. Therefore, for example, 3 cm, 6 cm, 10 c
It is preferable to provide them almost uniformly on the entire surface of the dam plate 1 at appropriate intervals of about m and 30 cm. For example, in the case of a non-through hole having a diameter of about 1 mm, a lattice or staggered lattice is provided at an interval of about 3 cm, and a through hole having a diameter of about 3 mm is arranged in a lattice or staggered grid at an interval of about 30 cm. What is necessary is just to provide in a shape. The larger the number of the air holes 4, the better the releasability from the hardened concrete. However, if the number of the air holes 4 is too large, the strength of the polyester film 2 may be reduced and the polyester film 2 may be easily broken. Further, the depth when the ventilation hole 4 is a non-through hole is not particularly limited, either.
It suffices that at least the polyester film 2 on the surface penetrates and reaches the inside of the weir plate 1, but it is better to penetrate through the weir plate 1 to release the concrete from the concrete.
The shape of the ventilation hole 4 is not particularly limited and is usually a round hole, but may be any other shape such as a long hole or a slit.

The method for providing the ventilation holes 4 is not particularly limited, either.
A vent hole 4 may be provided to penetrate the polyester film 2 and communicate with the paperboard 1 ′ using a drill, a drill, or the like, or to penetrate the back surface of the weir plate 1. In addition, the air holes 4 can be provided by passing the paperboard 1 ′ having the polyester film 2 laminated on the surface thereof under pressure in a roll provided with a large number of needle-like projections. Furthermore, for example, when using a board in which paperboard is laminated as the weir board 1, a board manufacturing process, a lamination process of a polyester film on the paperboard, a process of laminating the paperboard in a multilayer, and a pass through the roll The step of forming the pores 4 can be performed in a series of steps. Further, after forming a ventilation hole in the surface material on which the polyester film is bonded before the paperboard is multilayered, it can be bonded to another paperboard.

As described above, it is preferable that the weir board 1 made of the paperboard 1 'having the polyester film 2 adhered to the surface is subjected to a waterproof treatment on its small end face. For example, it is preferable to apply the waterproof paint to the four peripheral edges of the weir plate 1 or to adhere the waterproof tape 16 as shown in the figure to prevent the weir plate 1 from being flooded. As the waterproof tape 16 in this case, for example, an adhesive tape made of a synthetic resin such as polyester, polypropylene, or polyethylene can be used. When waterproofing the edge of the paperboard 1 ′ with the waterproof tape 16, the polyester film 2 on the surface from the edge of the paperboard 1 ′ as shown in FIG.
By sticking so as to overlap with each other, the edge of the fore edge can be waterproofed and the polyester film 2 can be prevented from peeling from the paperboard 1 'at the edge.

Further, as shown in FIG. 4, a wood board such as a plywood, a particle board, a hard board, a synthetic resin board, a lath board, etc. Back plate 15 made of
Are joined by screws, adhesive bonding, etc.
The board 1 'can also be reinforced to increase the rigidity to form the dam board 1. Also, by joining the back plate 15, the paperboard 1 '
Can be reduced in thickness. For example, instead of using the paperboard 1 ′ having a thickness of 6 mm, a back plate 15 made of plywood can be used as the dam board 1 by bonding a back plate 15 made of plywood to the back of the paperboard 1 ′ having a thickness of 3 mm. In this case, when the polyester film 2 on the surface is damaged by repeated use and cannot be used as a weir board, the back board 15 is removed from the paper board 1 ′, and the paper board 1 ′ is recycled as raw paper material, A new paperboard 1 ′ can be bonded to the back plate 15 and reused. The material of the back plate 15 is not limited to the above, and the thickness thereof is not particularly limited, and can be appropriately selected and used in consideration of strength, weight, and the like. For example, in the case of plywood, one having a thickness of about 3 to 12 mm may be used.

The weir plate 1 as described above is used in a state where the back surface of the weir plate 1 is reinforced with a support such as a support tree, like a conventional concrete formwork made of plywood or the like. For example, the one shown in FIG. 5 is made of paperboard having a polyester film adhered to the front surface thereof, and has a standard size of about 600 mm and a length of about 1800 mm (so-called 2 × 6 size), which are the standard sizes of the formwork. In addition, a reinforcing frame 51 made of a wooden bar is provided around the periphery of the support 5 and three reinforcing bars 52 also made of a wooden bar are provided inside the reinforcing frame 51 at predetermined intervals. The concrete form F is provided along the length direction of the weir plate 1. In this way, by providing the reinforcing frame 51 or the reinforcing bar 52 made of a wooden timber as the support 5 on the back surface of the dam board 1 made of paperboard, and forming the concrete form F, the concrete form F required for building is required. 3.5t
It is possible to achieve a pressure resistance of on / m ² or more. FIG. 6 shows a supporting frame 5 on the back surface of a dam plate 1 of the same size as the above, and a reinforcing frame 51 made of an aluminum square pipe is provided around the periphery thereof, and the reinforcing frame 51 is provided. 51 is a concrete form F in which two reinforcing bars 52 also made of angle iron and made of aluminum are provided at predetermined intervals along the length direction of the weir plate 1 inside 51. It is possible to achieve a pressure resistance of 5.5 ton / m ² or more required for a concrete formwork for civil engineering.

As described above, the concrete form F of the present invention in which the reinforcing frame 51 and the reinforcing bar 52 are provided as the support 5 on the back surface of the weir board 1 made of paperboard, as a result of repeated use, When the polyester film on the surface of the board 1 is damaged or becomes unusable, the support 5 including the reinforcing frame 51 and the reinforcing bar 52 is removed from the dam board 1 and recycled as a raw material for waste paper. The removed support 5 such as the reinforcing frame 51 or the reinforcing bar 52 can be reused as the concrete form F by attaching a new weir plate 1 thereto. In the case of the dam board 1 in which the polyester film 2 is stuck on both sides of the paperboard, both sides can be used as a concrete casting surface. By turning over the weir plate 1 removed from the shoring 5 such as the cross bar 52 and reattaching the shoring 5, it can be used as a concrete form F further, and the number of service times of the weir plate 1 increases.

The weir plate 1 and the support 5 provided on its back surface
There is no particular limitation on the method of joining with the reinforcing frame 51, the reinforcing bar 52, and the like. In a concrete formwork using conventional plywood, a timber (support wood) made of wood or the like is used as a support, and the support wood is joined to the back surface of the plywood as a weir board by nailing or the like. The dam board 1 in which the polyester film 2 is laminated on the paperboard surface and the dam board 1 in which ventilation holes are provided in the polyester film 2 according to the present invention are excellent in releasability from hardened concrete. The bonding strength between the plate 1 and the support 5 such as the reinforcing frame 51 and the reinforcing bar 52 on the back surface does not need to be so large. Therefore, it is possible to sufficiently use both of them simply by bonding them with a double-sided adhesive tape or the like. Needless to say, the weir plate 1 and the shoring 5 may be fixed with nails as in the related art, or further, may be fixed with screws or other means.

The material and structure of the reinforcing frame 51 and the reinforcing bar 52 as the support 5 are not particularly limited.
As shown in FIG. 6, a conventionally used supporting tree or the like can be used. In addition, for example, a metal or synthetic resin can also be used, and further, an aluminum as shown in FIG. If it is, both the weight reduction and the reinforcing effect of the concrete form can be satisfied at the same time, and even when the dam board 1 made of paperboard or the polyester film 2 on the surface is damaged, only the dam board 1 is used. By replacing, the supports 5 such as the reinforcing frame 51 and the reinforcing bar 52 can be used repeatedly. In this case, when the reinforcing frame 51 and the reinforcing bar 52 as the shoring 5 are integrally connected by, for example, welding, etc., the reinforcing frame 51 and the reinforcing bar 52 can be collectively attached to and detached from the dam plate 1. It is preferable because the work of attaching and detaching the plate 1 and the shoring 5 becomes easy.

The shape and structure of the reinforcing frame 51 and the reinforcing bar 52 as the shoring 5 are not particularly limited, but the reinforcing frame 51 provided around the back surface of the weir plate 1 is as follows.
For example, those made of square pipes as shown in FIGS. 6 to 9 are preferred from the viewpoint of weight reduction and reinforcement effect of the entire concrete formwork F. As the reinforcing bar 52, an angle steel as shown in FIGS. 6 to 9 is also preferably used from the viewpoint of the weight reduction and the reinforcing effect of the entire concrete formwork F.

The weir plate 1 in the concrete form F according to the present invention is obtained by laminating a polyester film 2 on the surface of a paperboard 1 ′ and further providing ventilation holes 4 in the polyester film 2. Although it has excellent releasability from the surface, it protrudes from the concrete casting surface 11 of the weir plate 1 into the support 5 composed of the reinforcing frame 51 and the reinforcing bar 52 provided on the back surface of the weir plate 1. By providing a flexible releasing means, the releasing operation from hardened concrete is further facilitated.

As the releasing means, for example, a releasing pin is provided on a reinforcing frame 51 or a reinforcing bar 52 as the support 5 so as to be able to come and go from the concrete casting surface of the weir plate 1. It is possible to use a device provided with a release pin provided so as to be able to protrude and retract from the concrete casting surface and a biasing means for biasing the release pin in a direction opposite to a direction in which the release pin protrudes from the concrete casting surface. it can.

For example, what is shown in FIG. 10 is a countersunk screw-like shape from the concrete casting surface 11 side of the weir plate 1 on a reinforcing frame 51 made of a square pipe provided as a support 5 on the back surface of the weir plate 1. The release pin 6 is screwed in, the rear end of the release pin 6 is attached in a state of protruding from the back surface of the reinforcing frame 51, and the end of the protruded release pin 6 is formed in a square shape to operate the operation section. 6a. Thus, the reinforcing frame 51
In the case where the release pin 6 is screwed into the concrete, as shown in FIG.
Is set so as not to protrude from the concrete casting surface 11 of the weir plate 1, and when releasing the concrete form F from the hardened concrete C at the time of concrete casting and demolding after hardening, the release pin 6 is A wrench or the like is appropriately attached to the square operating portion 6a formed at the rear end and rotated with an electric drill or the like, and the release pin 6 is poured into the concrete of the weir plate 1 as shown in FIG. By projecting from the surface 11, the concrete form F can be released from the hardened concrete surface C '.

FIG. 11 shows a release pin 7 provided so as to be able to protrude and retract from the concrete casting surface and the release pin 7.
The spring 8 is provided as urging means for urging the damper plate 1 in a direction opposite to the direction in which the damper plate 1 projects from the concrete casting surface 11. In this case, when placing concrete,
As shown in FIG. 11 (a), the release pin 7 is held by the spring 8 so as to hardly protrude from the concrete casting surface 11, and when the concrete is cast and hardened, the hardened concrete C is removed. From concrete formwork F
When the mold is released, the rear end 7a of the release pin 7 is removed.
Is hit from the back side of the concrete form F with, for example, a mallet, so that the release pin 7 protrudes from the concrete placing surface 11 as shown in FIG. It can be released from the concrete surface C ′.

Further, as the releasing means, as shown in FIG.
As shown in the figure, the release pin 7 is provided so as to be able to protrude and retract from the concrete casting surface 11 of the weir plate 1, and the base 9 attached to the reinforcing frame 51 or the reinforcing bar 52 as the support 5 When a base is used, the base 9 can be driven into the reinforcing frame 51 or the reinforcing bar 52 as the shoring 5 on the back surface from the surface (concrete casting surface 11) of the weir plate 1 and attached. This facilitates the work of attaching the releasing means.

Further, as shown in FIG. 10, as a releasing means, a countersunk screw-shaped one having a flange 6b at the tip is used as a releasing pin 6 provided to be able to protrude and retract from the surface of the dam plate 1. The flange 6b is used to support the surface (concrete casting surface 11) of the weir plate 1 or, as shown in FIG. Release pin 7 and Shoring 5
In the release means comprising the reinforcing frame 51 and the base 9 attached to the reinforcing bar 52, a flange 9a is provided at the tip of the base 9, and this base 9 is placed on the surface of the dam plate 1 (the concrete casting surface). 11) From the side, support on the back 5
In a structure in which the surface of the dam board 1 is supported by the flange portion 9a by penetrating and attaching the reinforcing frame 51 and the reinforcing bar 52, these releasing means are used for the dam board 1. It can also serve as a fixing means with the backing 5 on the back surface.

The position and number of the release means are not particularly limited. For example, in the case of a 2 × 6 size form shown in the figure, the reinforcing frame 51 provided around the back surface of the weir plate 1 is used. Of 4
It may be provided at about six places, that is, at the corners and at the center of the pair of reinforcing frames 51 in the long side direction.

Further, the dam board 1 made of paperboard in the concrete form F of the present invention tends to have a lower rigidity than the dam board made of a conventional plywood by itself.
2, a pair of opposed concrete forms F,
When the concretes F are connected between the two concrete forms F and F by connecting the Fs with the separators S, the periphery of the dam plate 1 to which the separators S are attached may be warped or curved. . Therefore, it is preferable that separator receiving members 10 as shown in FIGS. 6, 7, 9 and 12 are provided at appropriate intervals on the back surface of the weir plate 1 to prevent the bending of the weir plate 1. The separator receiving member 10 may have a long hole, a cross hole, or a large number of holes 10 as shown in the drawing.
It is preferable to use a plate material formed of No. 1. Thus, the separator receiving member 10 has a long hole or a cross hole,
Alternatively, by providing a large number of apertures 101, even if the arrangement of the opposed concrete forms F, F is shifted,
The connection position of the separator S in the separate receiving member 10 can be adjusted. Further, the separator receiving member 1
Reference numeral 0 denotes the reinforcing frame 51 or the reinforcing bar 5 as the support 5.
It is preferable that they are integrally fixed to 2. As described above, by fixing the separator receiving member 10 integrally to the support 5, the support 5 and the separator receiving member 1 on the dam plate 1 are fixed.
0 can be easily attached and detached, and the deformation of the dam plate 1 can be reliably prevented. Note that the separator receiving member 10 does not necessarily need to be provided.
As shown in FIG. 4, a dam board 1 in which a back board 15 is joined to a paper board 1 '.
In this case, the back plate 15 can prevent the deformation of the paperboard 1 'similarly to the separator receiving member 10.

Further, since a concrete form is usually used in a state where a plurality of forms are connected to each other, the concrete form F is used for connecting the plurality of concrete forms F to each other. It is preferable to provide a connecting means. As this connecting means, for example, as shown in FIG. 13, a connecting hole 53 is provided in a reinforcing frame 51 as a support 5 provided around the back surface of the weir plate 1, and adjacent concrete forms F, F are connected to each other. 14, the connection bolts 12 provided in the reinforcing frames 51 are passed through the connection bolts 12 and fixed with the nuts 13, or as shown in FIG.
Adjacent concrete forms F, F may have a structure in which reinforcing frames 51, 51 provided around the back surface of the weir plate 1 are connected and fixed to each other by clip-shaped fixing members 14. In this case, if the connecting hole 53 is formed as a long hole, it is possible to cope with a positional deviation between the adjacent concrete forms F.

[0050]

The following examples are given, but the present invention is not limited by these examples.

(Example 1) In a suspension using recovered corrugated cardboard as a fiber raw material, a rosin size agent 1.5%, a dry paper strength enhancer 0.3% and a wet strength were calculated based on the fiber raw material in terms of solid content. Water-resistant paperboard a having a basis weight of 500 g / m ² and a thickness of 0.75 mm by internally adding 0.1% of paper strength enhancer and 6% of sulfuric acid band.
And water-resistant paperboard b having a basis weight of 370 g / m ² and a thickness of 0.55 mm were produced. On the other hand, a film 3 having a thickness of 20 μm is prepared from a polyethylene resin by a T-die method, and as shown in FIG. 15A, the polyethylene film 3 is laminated on one side of the water-resistant paperboard b with an extruder laminator, and A 25 μm-thick biaxially stretched polyethylene terephthalate film 2 is laminated on the film 3, passed through a rubber roller and pressed against the film 3, cooled through a cooling roll, and cooled as shown in FIG. 15 (b). Polyester film 2 with polyethylene film 3 on one side
To produce a surface material 1a. Next, FIG.
As shown in FIG. 2, two water-resistant paperboards b are laminated on one surface of one water-resistant paperboard a, and 1
By laminating a sheet of water-resistant paperboard b and the surface material 1a with the polyester film 2 on the outside, a board 1A made of a water-resistant paperboard having a five-layer structure in which the polyester film 2 was stuck on one side was produced. The water-resistant paperboards a and b were press-bonded using a polyvinyl alcohol-based adhesive. The thickness of the board 1A made of the water-resistant paperboard having a five-layer structure in which the polyester film 2 was stuck on one side and thus produced was about 3 mm. further,
As shown in FIG. 15D, two boards 1 made of water-resistant paperboard having the polyester film 2 adhered to one side thereof
A, the two sheets are back-to-back with the polyester film 2 attached so that the sticking surface of the polyester film 2 is on the outside, and pressed and joined using a polyvinyl alcohol-based adhesive, so that polyethylene is attached to both sides of the board made of water-resistant paperboard. The dam plate 1 having a thickness of about 6 mm to which the 25 μm-thick polyester films 2 and 2 were adhered via the films 3 and 3 was manufactured.

The weir plate 1 having the polyester film adhered to both sides of the board made of paperboard manufactured as described above.
Is cut into a size of about 600 mm in width and about 1800 mm in length (2 × 6 size), and its four-circle small end face is covered with waterproof tape, and an aluminum support 5 as shown in FIG. To form a concrete form F, two concrete forms F are arranged opposite to each other to form a mold, and 25.4% by weight of cement is provided between the two concrete forms F, F.
10.29.2% by weight of sand, 34.3% by weight of gravel and water.
After casting concrete mixed at 1% by weight (water / cement ratio = 0.437) and curing and hardening for 4 days, it is released from the hardened concrete, and the mold releasability and the condition of the concrete surface and the surface of the dam board are examined. The operation of placing concrete again was repeated, and even if the concrete was placed 10 times, the releasability from the concrete was good and the finished condition of the concrete surface was good. No abnormality such as tearing or peeling was observed in the film, and the film was in a state where it could be used further repeatedly.

(Example 2) A polyester film having a diameter of about 1 mm
The concrete pouring test was performed in the same manner as in Example 1 except that the vent holes were formed in a staggered pattern at intervals of about 3.5 cm on the entire surface of the weir plate 1 without penetrating both sides of the weir plate 1. As a result, even if concrete was cast 10 times, the releasability from concrete was still better than that of Example 1, and the finished condition of the concrete surface was good.
No abnormality such as tearing or peeling was observed on the polyester film on the surface of the weir plate, and the polyester film was in a state where it could be used further repeatedly.

(Example 3) A polyester film having a diameter of about 3 mm
Are formed in a staggered pattern at intervals of about 30 cm on the entire surface of the weir plate 1 in a state of penetrating through both surfaces of the weir plate 1.
A concrete casting test was conducted in the same manner as in Example 1. As a result, even if concrete was cast 10 times, the releasability from concrete was still better than that of Example 1, and the finished condition of the concrete surface was good. No abnormality such as tearing or peeling was observed on the polyester film on the surface of the weir plate, and the polyester film was in a state where it could be used further repeatedly.

(Example 4) A board 1A having a thickness of about 3 mm and made of a water-resistant paperboard having a five-layer structure and having a polyester film 2 adhered to one side, prepared in the same manner as in Example 1 (FIG. 1)
5 (c)), a 3 mm-thick plywood back plate is screwed to the back surface of the back plate to form a weir plate, and the back surface is provided with a support tree made of a wooden square as shown in FIG. Using a frame, a concrete casting test was conducted in the same manner as in Example 1. As a result, even if concrete was cast 10 times, the releasability from concrete was good, and the finished condition of the concrete surface was good. No abnormality such as tearing or peeling was observed on the polyester film on the surface of the weir plate, and the polyester film was in a state where it could be used repeatedly.

(Comparative Example) Instead of the barrier plate of Example 1, concrete in which a support bar made of a wooden square as shown in FIG. 5 was provided on the back surface of a conventional barrier plate made of plywood with urethane coating on the surface. When a concrete casting test was performed using the formwork in the same manner as in Example 1, the mold release from the concrete was relatively easy up to the third time, but the mold release deteriorated each time the concrete placement was repeated. When the concrete was cast eight times, it had to be released with a hammer.

[0057]

As described above, the concrete formwork according to the present invention is obtained by adhering a polyester film to the surface of a weir board made of paperboard, so that the finished surface of the hardened concrete is good and the concrete form is made of concrete. Because of its excellent mold release properties, it can be used repeatedly.In addition, weir boards can be manufactured using recycled paper, and after use, they can be recycled as raw materials for used paper. It can contribute to resource conservation by reducing the amount of wood board used.

[Brief description of the drawings]

FIG. 1 is a schematic partial sectional view of a dam plate showing one embodiment of a concrete formwork of the present invention.

FIG. 2 is a schematic partial sectional view showing another embodiment of the weir plate.

FIG. 3 is a schematic partial sectional view showing still another embodiment of the weir plate.

FIG. 4 is a schematic partial sectional view showing an embodiment of a weir plate in which a back plate is joined to paperboard.

FIG. 5 is a perspective view showing the embodiment of the concrete formwork according to the present invention, as viewed from the back side.

FIG. 6 is a perspective view showing another embodiment of the concrete formwork according to the present invention as viewed from the back side.

FIG. 7 is a rear view of the concrete formwork shown in FIG. 6;

FIG. 8 is a plan view of the concrete formwork shown in FIG. 6;

FIG. 9 is a sectional view taken along the line II in FIG. 7;

FIG. 10 is a cross-sectional view of a main part of a concrete formwork showing one embodiment of a mold releasing means.
(B) shows the state at the time of demolding.

FIG. 11 is a cross-sectional view of a main part of a concrete formwork showing another embodiment of a mold releasing means, where (a) is a view at the time of placing concrete.
(B) shows the state at the time of demolding.

FIG. 12 is a cross-sectional view showing a state in which opposed concrete forms are connected by a separator and concrete is poured.

FIG. 13 is a perspective view of a main part showing one embodiment of a connecting means of a concrete formwork.

FIG. 14 is a perspective view of a main part showing another embodiment of the connecting means of the concrete formwork.

FIGS. 15A to 15D are process explanatory views showing a method for manufacturing a weir plate.

[Explanation of symbols]

1: dam board, 1 ': paperboard, 2: polyester film,
3: adhesive layer, 4: vent hole, 5: support, 6: release pin,
7: release pin, 8: spring, 9: base, 10: separator receiving member, 11: concrete casting surface, 12: connecting bolt, 13: nut, 14: fixture, 15: back plate, 16:
Waterproof tape, 51: reinforcing frame, 52: reinforcing bar, 53:
Connection hole, 101: opening.

Claims (12)

[Claims] 1. A concrete formwork comprising a polyester film adhered to at least a concrete casting surface of a board made of paperboard. 2. The concrete formwork according to claim 1, wherein said paperboard is made of a board in which water-resistant paperboard is laminated in multiple layers. 3. The concrete formwork according to claim 2, wherein the water-resistant paperboard is made of 75% by weight or more of recycled paper. 4. The concrete formwork according to claim 1, wherein the polyester film is adhered to the surface of the paperboard via an adhesive layer made of a thermoplastic resin to form a weir plate. 5. The concrete formwork according to claim 4, wherein a thermoplastic resin film is used as the adhesive layer made of the thermoplastic resin. 6. The concrete formwork according to claim 4, wherein the thermoplastic resin is polyethylene. 7. A laminate of a thermoplastic resin film melted by extrusion lamination on one side of a paperboard, and a polyester film laminated on the thermoplastic resin film and pressed to adhere the polyester film to the surface of the paperboard. The concrete formwork according to any one of claims 1 to 6, wherein a single or a plurality of paperboards are bonded to the paperboard with the polyester film bonding surface facing outward to form a dam board. 8. The concrete formwork according to claim 1, wherein ventilation holes are provided in said polyester film. 9. The concrete formwork according to claim 8, wherein a polyester film is laminated on both sides of the paperboard, and the ventilation holes are provided in the polyester films on both sides. 10. The concrete formwork according to claim 8, wherein the ventilation holes are provided through both sides of the weir plate. 11. The concrete formwork according to any one of claims 1 to 10, wherein a watertight treatment is applied to a small end face of the dam board made of paperboard. 12. The concrete formwork according to claim 1, wherein a back plate made of a wood board such as a plywood, a synthetic resin board, a lath board, or the like is joined to a back surface of the paperboard to form a weir board. .